割苗对夏玉米生长发育、产量及抗倒伏性能的影响

Effects of Cutting Seedlings on Growth, Yield and Lodging Resistance of Summer Maize

倒伏严重影响夏玉米的高产稳产,本研究旨在探讨割苗对夏玉米生长发育、产量和抗倒伏性能的影响。本试验2016年分别选用郑单958和DH618于三叶期(V3)割苗、登海618于拔节期(V6)割苗,2017年选用浚单20和登海605分别在V3和5叶期(V5)割苗。结果表明:与对照相比,割苗处理夏玉米的生育进程推迟2~8天;穗粒数和千粒重显著降低;V3割苗比对照产量降低0.7%~6.8%,V5割苗比对照产量降低18.9%~32.4%,割苗越晚产量降低越严重。割苗后夏玉米抗倒伏性能显著提高,并且V5割苗处理提升最显著:与对照相比株高降低6.9%~10.6%,穗位高降低16.5%~19.6%;基部第三节间茎秆穿刺强度提高30.1%~34.2%,节间长降低56.2%~58.6%;茎秆小维管束数、皮层厚度和硬皮组织厚度显著提高,并且V5割苗对其影响大于V3割苗。结论:割苗显著改善夏玉米茎秆形态学特征和力学特征,进而提高夏玉米抗倒伏能力;但是由于割苗后夏玉米生育期内光合产物减少,导致夏玉米产量显著降低,并且割苗越晚产量降低越严重,因此不宜在夏玉米生产中应用。

Lodging seriously affected the high and stable yield of summer maize.The experiment was conducted to investigate the effects of cutting seedlings on summer maize growth and development,yield and lodging resistance.In 2016,ZD958 and DH618 were used as materials to cut seedlings at the 3-leaf stage(V3)and 6-leaf stage(V6)respectively;and in 2017,XD20 and DH605 were used as materials to cut seedlings at V3 and 5-leaf stage(V5)respectively.Compared with the control,the growth process of summer maize was postponed for 2~8 days and the grain number per spike and the 1 000-grain weight were significantly lower under cutting seedling treatments.The yield of V3 treatment reduced by 0.7%~6.8%,and that of V5 treatment reduced by 18.9%~32.4%compared with the control.The later the seedling was cut,the more serious the yield reduced.After cutting seedlings,the lodging resistance of summer maize was significantly improved,and the V5 treatment had the most significant effect.Compared with the control,the plant height decreased by 6.9%~10.6%;the ear height decreased by 16.5%~19.6%;the stalk rind penetration strength increased by 30.1%~34.2%;the length of the third basal internode decreased by 56.2%~58.6%;the number of small vascular bundles,cortex thickness and rind thickness of the stem increased significantly,and the influence of V5 treatment on them was greater than that of V3 treatment.In conclusion,cutting seedlings could significantly improve the lodging resistance of maize plants by improving the morphological and mechanical characteristics of stem stalks.But cutting seedlings significantly reduced the yield of summer maize due to the reduction of photosynthetic production after cutting seedlings,and the later the seedlings were cut,the more serious the yield reduction was.So the treatment of cutting seedlings was not suitable in summer maize production.